NOTE: On some speedlights, including the SB400, SB700, and the Pop-Up flash, there is no selector for iTTL and iTTL-BL. To switch between these two modes on these speedlights, you switch the camera metering mode. Matrix and Center-Weighted force the speedlight into iTTL-BL mode. Spot metering forces the speedlight into regular iTTL mode.

The flash system will control the exposure of the subject no matter you do to the ISO, Aperture, or Shutter (within the range limts of the flash).

The shutter will primarilly control the background exposure. Increase the shutter to stop ghosting at the expense of a darker background. Decrease the shutter to brighten the background, at an increased risk of ghosting.

The aperture will primarilly control depth of field. Widen the aperture to decrease depth of field, increase background exposure, and increase flash range. Narrow the aperture to increase depth of field, decrease background brightness, and reduce flash range.

HIGH AMBIENT:
In high ambient conditions your flash will be adding FILL. This means the flash will be secondary to the ambient light in creating your images. The flash will brighten the shadows on the subject's face and clothing. The power of the flash must be adjusted to balance with the ambient light to make the subject equal brightness to the background ambient. You should use iTTL-BL flash mode to allow the flash to adjust itself automatically to balance the subject with the ambient.

If direct sunlight is hitting the subject's face, move the subject into the shade. If that is not possible, turn off the flash to avoid overexposure (blow out) of the subject's face.

Recommended intitial settings:
Camera P mode, ISO 200, iTTL-BL
This is the simplest setting I recommend at first until you more fully understand everything. These settings will add nice Fill to your shots.

MEDIUM AMBIENT:
Medium ambient is by far the most difficult situation to use your flash. It is also the time when if you use your flash right, it will greatly improve the quality of your images, but if you use it wrong, it will destroy your images.

In medium ambient you have to make several more decisions to determine the initial settings. You have to decide how you want to shoot:
Do you want the flash to be primary?
CAN you even make the flash primary?
Or do you want the flash and ambient to balance on the subject?
Or do you want the flash to be only light Fill and the ambient primary?
Or do you have to turn off the flash and shoot available light?

Then you might ask, why would I want the flash to be primary?
Well, the most frequent reason would be when the ambient light was some funny color, like bright mercury vapor lamps (gymnasium). The flash is the color of daylight, so you would then have a weird multicolored image since there is no single white balance that can be chosen. The only way to get proper colors in this situation is to either turn off the flash and use a white balance that matches the ambient or eliminate the ambient by making the flash primary.

A second reason you might want the flash to be primary would be if you are shooting a subject that is moving quickly (dancers, runners). You can eliminate ghosting and blur if you make the flash primary, since the flash will then freeze the motion because its duration is only about 1/1000th sec.

HOW TO MAKE THE FLASH PRIMARY:

To make the flash primary, you have to make the flash overpower the ambient light. This must be done with the flash in iTTL mode by decreasing the exposure by three stops or more with shutter and ISO from the ambient setting you measured with the camera meter above.

Example 1: Assume the results of your metering step above came out to f/4.0, ISO 400, and 1/60th. You would then recognize that you were in Medium Ambient Conditions, so you must immediately change the ISO to 200. This decreases the ambient exposure one stop.

Then increase the shutter by two stops to 1/250th (double it twice and pick the closest setting - 1/60th-->1/120th-->1/240th). Notice that the highest shutter speed you can select when in regular flash sync (on a D200) is 1/250th. Now, you have changed the settings so the camera will underexpose the ambient by three stops. This example is right on the edge of where you might have to turn off the flash and shoot available light or switch to TTL-BL and go for balanced fill. In fact, if your camera is a D80 it has a maximum flash sync speed of 1/200th, so you would not be able to fully overpower the ambient in this situation.

IMPORTANT POINTS:

1) It is important to understand that when using the flash in regular iTTL mode, the flash metering system does not measure the ambient, so whatever flash power it determines is as if you were in pitch dark conditions. This causes the ambient to add to the flash on the subject and if the ambient is not totally overpowered, it can easily overexpose the subject. So, if you cannot totally overpower the ambient, and you still want to use iTTL mode, YOU MUST REDUCE THE FLASH POWER using the FEC button to avoid overexposure. The amount you must reduce it is a judgement call, making flash in medium ambient conditions that much more difficult.

2) In iTTL-BL mode the flash DOES measure the ambient, and then sets the flash to make the subject equal brightness to the ambient. This will only work well, however, if the ambient light is the same color as the flash (ie, daylight). If the ambient is something light mercury vapor, don't use iTTL-BL. Also, it is important to understand that TTL-BL will only work correctly when the camera is set for a normal ambient exposure. P mode makes this easy, since the camera will automatically set itself for a normal ambient exposure.

Note: On the SB-600, 800, and 900 Speedlights there is a mode selector to put the flash in either iTTL or iTTL-BL modes. ON the pop-up flash and the SB-400 and SB-700 speedlights, you control the selection of iTTL or iTTL-BL from the camera using the metering mode selection. If you select Matrix or Center-Weighted metering, you will get iTTL-BL mode. If you select Spot metering, you will get iTTL mode. It shows this in the display of the SB-700 but not the SB-400.

Example 2: Assume the results of your metering were ISO 400, 1/200th, and f/4.0. You should immediately see that you will have major problems reducing the exposure of the ambient by three stops. You can't double the shutter, because you are already near maximum flash sync speed. That leaves only ISO and Aperture. You can reduce the ISO to 200 and that gets you one stop, but the only way to get the other two stops is to stop down the aperture by two stops (f/4.0 --> f/5.6 -- f/8). But if you change the aperture to f/8, the flash range will become less than six feet or so (using a diffuser), so that may not be an option. In fact, if this is your situation, you are forced to abandon the idea of overpowering the ambient light.

You must now consider balancing the flash to the ambient.

HOW TO BALANCE THE FLASH TO MEDIUM AMBIENT CONDITIONS

If you find yourself in a situation like Example 2) above, you could decide to turn off the flash and shoot available light or you could decide to balance the flash to the medium ambient.

There are two approaches to balancing the flash to medium ambient conditions:

1) In iTTL mode you reduce the flash compensation manually by trial and error until the right flash power is determined. I am not going to discuss this method.

2) In iTTL-BL mode, the flash system will set itself automatically. This is the approach I will now discuss.

Camera P mode, Flash iTTL-BL, ISO 200. (notice that these are the same settings as for High Ambient conditions).

This will give you nicely balanced images with bright backgrounds and bright subjects. You might want to apply some negative flash compensation, say -0.3 ev, to keep it from looking like the subject is jumping out of the picture.

You might be tempted to use camera A mode, and it can be done, but you have to be very careful to prevent overexposure. The shutter is limited to 1/250th (or 1/200th) flash sync speed, and since it can't go any higher than that, if you choose an aperture that is too wide, the shutter will bang into the limit and your images will all be overexposed. P mode fixes this problem.

Incidentally, among professional photographers the joke is that P mode stands for 'Professional' mode, because we all use it in bright ambient when shooting fill flash. For some reason, beginning photographers avoid P mode like the plague. P mode has its important uses, and shooting iTTL-BL is one of them (especially in bright ambient).

CONCLUSIONS:

1) You must learn to use your camera metering to measure the ambient light

2) Low ambient situations are the easiest to learn to shoot flash. These are also the most common, and occur almost all the time indoors at parties, receptions, family time, etc. Use the recommended settings for exceptional flash shots every time.

3) High ambient light situations are also easy to shoot flash. This situation occurs every day outdoors during daylight. Let the wonderful iTTL-BL mode do all the work for you.

4) Medium ambient light makes flash photography very complicated, but the results are well worth it. This is the situation you have to really study in order to learn how to do it right.

126 comments:

Hi Russ, Thanks so much for a great summary to a terrific series. I use a D90 with an SB-900. I found your CLS Blog about 10 days ago and have been reading it and all the comments since. At this point at least I can understand quite well what you are summarizing here . I will study blogs 1-5 again and continue practicing. I feel quite confident using flash in most situations. Thank you so much for the information you have provided. I did not realize that you still posting new info to this series. Ted Thelin

Is there any disadvantage to just leaving the Auto FP high speed sync on all the time? I understand that the flash emits differently (rapid bursts throughout the shutter being open?) vs. a single flash. But, I don't know if this just occurs above 1/250 (I have a D90) or below it, as well, which would suggest that perhaps leaving it off might be a better option.

However, Auto FP High Speed Sync mode is a really wonderful mode for specific situations. It is fantastic on a bright sunny day when taking a portrait, because it will allow you to use a wide aperture to blur the background and still add fill. With normal Flash Sync, your shutter is restricted to 1/200th, so you have to stop down with the aperture to control the exposure.

Hi Russ,I'm very thankfull for your perfect work on Nikon Cls. It's by a wide margin the best and completest info on CLS. JoeMc Nally is good on practical use of Cls but you help to understand why Cls do things so or so.

ok, I have been reading all your post, but theres still a little question nagging at me. How can I use a Speedlight as a fill only of camera in a softbox (or shot-thru umbrella). Just as I use TTL-BL with on camera flash.Do I use normal CLS TTL? Is my lighting ratio the same when I start to move around with my object and flash?Or is it better for consistent results to switch to manual on the flash?In my shooting style I often move on location and use the ambient (aka sun) as main and one or two speedlights as fill. Until now I used SB-26s on full manual, but its a pain to adjust them if the range flash-subject is changing.Recently I bought two SB-600 and hoped for a little lazy TTL. With only a little fec on the camera. What do you think?

When I shoot portraits outdoors, usually use an SB800 on-camera with a big diffuser for extra fill. I use the sun and a reflector for the main and fill, and then shoot TTL-BL to lift the last of the shadows. I adjust the power of the flash up or down as needed.

Ocassionally, I use two umbrellas for formal wedding shots outdoors using Wireless TTL. TTL-BL is not available when flashes are in Remote mode, so as I mentioned in the blog, when using regular TTL, the flash adds to the ambient, so you always have to use negative FEC. I start with both flashes turned down by -0.7 ev. This usually gets me close.

When I shoot a portrait ouside with umbrellas, I do the same; Wireless TTL and negative FEC.

The problem with TTL (Wireless or on-camera) is that as you move around, the power changes to attempt to expose the subject to the same standard amount. This is sometimes not desireable, so if I plan to move around a lot, I usually switch to Wireless Manual flash and control the power of the flashes from the commander. Then, no matter what you do, the power will stay the same on each shot. But if you want to change it, the commander makes it quick and easy.

Hi Russ,Would you comment on which WB settings to use in different situations? Is it as easy as using Flash where flash is the predominant light and sunny when outdoors in bright light. How about when using BL indoors when the subject is standing in front of a window? Excuse me if I missed this in your blogs and just direct me where to read it.

The color of the flash is 'mid-day daylight'. Therefore, there are usually no white balance problems when using the flash for fill outdoors. You can use WB Auto, Flash, or Daylight. They will all give you approximately the same results.

Sometimes when shooting late in the day during the golden hour, the color of the daylight warms considerably, and then you might want to add a CTO gel to your flash to keep it from washing out the nice warm setting sun. Just keep the flash power low, so it won't change the basic appearance of the setting sun.

Is there a specific reason that you left out the option to use filters on the flash to balance the light colors of flash and ambient?I find this a very useful way especially in medum or high ambient conditions.I usually take a photo without flash at daylight-WB and chose a filter to produce the same color cast on the flash. This may not give an exact result, but the matching is usually rather good (checked after applying the filter and switching the flash on).

I debated whether ot not to add how to do simple balancing with tungsten or fluorescent lamps, but in the end I felt that topic was a bit more advanced than I wanted to get with this particular posting.

Actually, I am already working on on a new post that discusses essentially the same approach you described. However, I want to stick to only the gels that come with the SB-800, so I don't plan to go into such advanced topics as balancing with sodium vapor.

I think I will go back and add this info to this post, in case others are wondering the same thing as you.

Now I'm reading your last Blog, and it comes in very handy, as usual...

A short question tough:You wrote to determine ambient light:"6) Adjust the shutter to zero the meter" => I didn't understand what you mean by adjsusting the shutter zero; why we can't use the camera in Aperture priority mode, by selecting f/4.0 and ISE 400 as you suggested, to check the shutter speed that camera would calculate?

In the conditions I listed at the beginning of that paragraph, I said to put the camera was in Manual mode. In Manual mode, you have to use the built-in light meter (called the analog exposure meter in the Nikon User's Manual) to set the shutter and/or aperture. You adjust the shutter to 'collapse' the dots into the center of the display.

Yes, you could use the camera in A mode and let it automatically select the shutter speed. I chose camera Manual mode for no particular reason, except that everyone should learn to set the camera in Manual mode.

Great summary. I love it. I'm thinking I might print it out and keep it in my camera bag as a reference!

I have 2 questions though:1. Your recommended settings always suggest ISO 400. Is there a reason for this? Whether using a flash or not, I'm usually inclined to start at 200 (on my D90) and only increase this when necessary (i.e. the image is underexposed).2. In one of your responses to an anonymous user, you said that "Auto FP mode is useless for stopping action". Can you explain this in more detail? I understand how FP sync mode works (i.e. it pulses the flash as the front/rear shutter curtains 'scan' across the sensor), but let me think out loud here. If the maximum speed of the shutter mechanism is 1/200th second, say, then the flash will pulse several times during that 5ms time period. This would mean that the sensor would record the image in bursts with up to 5ms separating the time at the top of the sensor vs the bottom. Presumably, if photographing a fast moving subject, it will have moved some distance between the top and bottom of the sensor. Assuminh I have correctly explained this, does the subject really move an noticable amount in 5ms?

The reason I suggest ISO 400 is that I also suggest f/4, 1/80th as a starting point. If you use ISO 200 with f/4 and 1/80th the backgrounds will be too dark in normal indoor lighting. Also, ISO 400 and f/4 give you about 15 feet of flash range when using a diffuser.

The reason for f/4 is that it gives you reasonable depth of field for party shots, which allows you to shoot small groups and have all the faces stay sharp. If you use f/2.8, you will have lots of soft faces. If you use f/5.6, you will reduce the range of your flash.

The reason for 1/80th is that it stops most casual motion which decreases unwanted ghosting. Shutter speed (below flash sync speed) does not affect flash range.

The last reason for fixed ISO 400 is to keep the color balance the same in all shots. If you shoot some at ISO 200 and some at ISO 400, the color balance will be different for the two.

So, ISO 400 is just a suggested starting point. ISO 200 might be better in a very brightly lit room. ISO 800 might be better in a very dim room. However, once you choose an ISO, stay with that ISO for the whole event as long as the lighting stays constant.

About the Auto FP Mode:

First, the flash is not pulsed during Auto FP mode. I don't know where that myth came from. It is fired at a lower intensity and stays on continuously while the shutter is open. There is no reason they have to be pulsed during the shutter period. The flash tube is simply fired in a lower energy state, so that the capacitor will have enough charge to maintain that state over the 1/200th (or 1/250th second on a D300) flash sync speed.

If you are old-school, you can think of Auto FP mode as a fast flash bulb. It acts exactly the same as 1/200th second flash bulb.

1/200th sec (5 ms) is a pretty short time, but things like bird's wing tips and baseballs can move quite a bit of distance in that time. The ball coming off a baseball bat can be traveling at 300 mph, and at that speed, it will go 2.2 inches in 5 ms, so it will be very blurred if you don't increase the shutter speed.

If you select a shutter speed that is lower than 1/200th, and Auto FP is turned ON, it will still use normal flash mode, and the flash power will remain maximum and the duration of the flash will be around 1/1000th sec. This would stop most of the blur of the ball, but the low shutter will allow ghosting, so the blur will be there in addition to a frozen image.

If you increase the shutter speed above 1/200th sec, the flash power starts to decrease. If you select 1/1000th sec, the flash power will be reduced so much that it will no longer contribute much to the image.

This is what I meant by saying that Auto FP is useless for stopping action. It's the shutter that stops the action in daylight when using Auto FP mode.

So, the only real purpose of Auto FP mode is to allow you to use a wide f/ stop, to blur the background, while shooting fill flash in bright light.

"...the flash is not pulsed during Auto FP mode... fired in a lower energy state, so that the capacitor will have enough charge to maintain that state..."

I'm a little confused about this. If it was continuous, then shouldn't the flash power become higher as shutter speed increases rather than reduce? In other words, if capacitance is constant, wouldn't shorter discharge times (faster shutter speed) yield more power?

I have never done much macro photography, so I am not sure of all the difficulties. I do know that you would only use regular TTL, and never TTL-BL. I also know that when you are very close to your subject, it is easy to apply too much flash, and I don't think a flash like SB-800 is really very well suited to the task when mounted on-camera. That's why they make the Nikon R1C1 Kit which includes two SB-200 close-up flashes and an SU-800 Controller.

You have to understand more about how a flash actually fires to understand this.

The main capacitor is charged by the batteries until it is full. This full charge is then 'dumped' into the flash tube to fire the flash. For a normal flash, the full charge is applied directly to the flash tube and it discharges through the flash tube with no control other than ON or OFF. This fires the flash tube in the highest energy state which makes the most efficient and brightest pulse.

In Auto FP mode, the flash inserts some electronic control circuitry between the capacitor and the flash tube to reduce the voltage that is applied to the flash tube. This causes the tube to fire at a lower energy state which makes much less brightness, but it can stay on longer. This lower energy state requires less charge per sec from the capacitor, so it allows the tube to stay fired for the full 1/250th sec.

The downside is that the efficiency of this lower energy state is not as good as a regular flash. This means that more of the charge from the capacitor makes heat instead of light. This means that the overall total flash energy emitted during the FP flash is less than the amount emitted during a regular flash. This is why the flash range is decreased so much when using FP flash mode.

Incidentally, You may have noticed that towers with strobes on them to warn airplanes change just the same way from a bright fast flash in the daytime to a long slow flash at night. They do it in the very same way, by firing the tube in a lower energy state and keeping it on longer.

Your incredible posts are invaluable to all of us who own Nikon flashes. Your posts should be a mandatory reading for all Nikon CLS users and I really mean it. Just plain "thanks" is not good enough to express how thankful we are to you for your immense knowledge and blog. Usually I see that people with this type of knowledge tease you with few tips and then try to sell the rest. But you are exceptional and we thank you very much for it. Please keep them coming. Have a blessed New Year and many more happy returns.

Hi Russ! Thanks for your articles! And Happy New Year! I've got a question that I can't seem to find an answer to anywhere.

1. Suppose I've got an SB800/SB900 as a commander on my camera. Then I can set it up to work in the following configuration: the commander acts as an on-camera iTTL, while slave flashes in Group A act as a manual flash, power defined by the commander. It works, I've tested it.

2. Now suppose I use a simple iTTL flash (say, SB-400) connected to my camera via SC-28 or SC-29 cord. The end of the cord that holds the hotshoe also has a three-pin socket for SC-27 cord. Now to the question: what happens if in this configuration I connect a dumb flash (say, SB-28) in manual mode via this SC-27 cord to the SC-28 cord? Will my SB-28 trigger as needed (i.e. ignoring the pre-flashes)? I don't have the SC-27 to try it out myself, hence the question. The idea being - to use iTTL for key, while using manual for fill, sort of like in (1), but without the wireless.

Unfortunately, I do not have an SC-27 cord either, and I really don't know if it will work or not in the configuration you described.

As you probably know, The SC-27 cord was designed for the TTL that was used for film (and the D1/D100). It won't work for iTTL.

Consequently, I do not think it will work correctly, but you never know. It may work, since all you need is the fire signal, which occurs only after all the preflash sequence is completed.

If you decide to try this, please come back and report your results here, or email me at russ@russmacdonaldphotos.com .

I have tried something similar (that did not work). I thought that I could hook up a PC Cable to the output on the camera and use that to fire Slaves while using the on-camera flash in iTTL mode. However, I found that the PC Sync signal from the camera is disabled whenever the flash is used in iTTL mode. I suspect the SC-27 cable will be disabled in a similar way when using iTTL.

Just realized that I should have read all your posts before I left the comment I wrote on your earlier one ... :p with your great tips on using flash, I should have gotten better shots ... now I have to read this again & again until I got the useful tips deep down in my mind... thanks!! :)

Russ, excellent blog, thanks indeed.Your recommended settings for low ambient are 1/80s, yet the definition of low is up to 1/30s.The medium ambient goes from 1/30s upward.Is that a typo on your behalf, as an ambient setting of 1.5 stops would reduce the bkgds accordingly?

1/80th shutter is a recommended INITIAL setting. You may want to change it.

The whole point of making the flash primary is to underexpose the ambient by two to three stops, so it doesn't contribute to the exposure of the subject. With the ambient at 1/30th and the shutter at 1/80th, that's only 1.5 stops, so it might be better in that case to set the shutter at 1/120th to make the ambient a full two stops underexposed.

Yes, underexposing the ambient darkens the background, but that is the trade-off you need to make to keep the flash primary, and it is usually not a problem. As long as you can see the background, it is usually fine.

If you want the background to be exposed normally (in this example), then you have to set the shutter at 1/30th. This will mean the flash will no longer be primary, which greatly increases the difficulty of getting proper subject exposure. You have to then reduce the TTL flash power significantly using FEC to avoid overexposure of the subject. This is a hit or miss proposition and very difficult to hit right on the first try, especially if you are shooting quickly.

Your blog is amazing, but I desagree with you on use P in outdoors. I think M mode is the best way to have full situation control. If you move just a little the camera angle, the P mode change the exposition parameters.

Your blog is amazing, but I desagree with you on use P in outdoors. I think M mode is the best way to have full situation control. If you move just a little the camera angle, the P mode change the exposition parameters.

I don't disagree with you. In fact, I use camera Manual mode quite often when shooting outdoors.

I wrote this blog mainly for people who have ended up with blown images by turning on the flash outdoors and leaving the camera in A mode. Those are the people who should switch to P mode to make sure they don't blow out their images.

Also, I usually use P mode (and TTL-BL) when shooting fill for wedding pics outside, because I don't have time to set up the camera in Manual mode. Things just move too quickly, and my main concern is to capture a usable image.

Hi Russ, it's been a real pleasure finding this blog on the net. Now I think I'm finding my way in flash photography. I didn't apply seriously for a long time but now I'm totally into it (it's becoming really expensive too!).I've been asked from a friend to be her wedding photographer in a few months and now I'm studying hard to be comfortable with all my equipment on her special day.I've just upgraded from my old D80 to a D300s and I'm playing with the SB-600 I already owned. It's a real pleasure to follow all your tips and tricks and to see how the camera and the flash communicate together.

I wanted to ask you if you do use the light sphere diffuser for outdoor shots too or you go by direct light pointing the flash head toward your subject.

I'm planning to be alone on that day so there should be no one to help me holding a reflector eventually. Should I find a friend to help me? Do you think it would be better to buy also an SB-900 so I have two flash units just in case?

It will be stressfull shooting your first wedding, but everyone has to start somewhere.

Yes, I always use the Light Sphere outdoors if I can stay close enough to my subjects. Of course, outdoors, the flash is only adding fill, so it normally doesn't have to add that much to balance the subject with the ambient. If I can stay within 25 feet, I can usually get enough fill even with it pointed straight up.

My main advice is keep it simple. You don't need a helper. It will only confuse things.

Always get the shot! Don't worry about reflectors or umbrellas. Just make sure you get all the key shots. It way more important to capture the kiss than it is to get the right lighting ratio.

Same with the formal shots. I've used my Light Sphere lots of times for the formals without ever setting up any umbrellas. It works great. Besides, it's far more important to get all the correct groupings than to set exactly the right lighting on the groups.

I would make sure to have a backup camera, flash, and lens just in case something happens to one of those pieces of equipment.

If you would like further discussion on this, please email me at russ@russmacdonaldphotos.com. I don't want to move too far off-topic for my blog.

Hi again Russ.My name should be click-able to a Flickr stream with a set of photos showing an event I will be shooting Saturday. If that link does not work, may I converse via e-mail with you pls?These were taken at the same time as the venue will take place, so lighting (all things being equal) should be similar. I have also tried to include views of the venue to help in bounce decision making etc.I have a few questions around that set if you don't mind pls?Referring to each image by number, I have posted the exif for the shot to help guide me in correcting my errors?

1.1 Lobby:Door open, 1/500s to retain the outdoors.Indoor way underexposed.Bounce was by larger than normal home made betterbouncecard 60deg straight up.

1.6 Lobby:From your cookbook I should have gone low ambient settings, i.e. TTL and not BL, ISO400 not 200? The direct flash behind the lady on the door is distracting too.

1.4 the Aisle walk:Where to bounce (if any) as the shadows are highly visible here. The vertical orientation adds wonderful harsh shadows to the benches too!

1.2 Where the couple will be standing, so many shots from this view. Note the high? ceiling and far away walls for bounce (or lack thereof?) Also check the awesome vertical orientation shadows again?

1.5 The audience:To give you an idea of the ambient and further layout, an audience shot is included.

1.3 Groom position: May take some shots of the couple from that angle too.

Many questions then pls? Suggested areas (if any) to bounce from? Bounce with or without bounce card?FV comp required? Flash mode to use (I would gather TTL as ambient is low). Is there any hope for a decent set of pics from this scenario without going way overboard on budget etc? Should I get closer, further away? Any and all ideas you have would be ever so highly appreciated!

Terribly sorry for intruding on your free time, but desperation requires knowledge.

Thanks for that link. I think I now understand where the idea that the flash is pulsed comes from.

What they have done is to pulse fire the flash rapidly without allowing the capacitor to ever discharge far enough for the light output to drop down significantly.

This results in a pulsed flash tube, but a continuous output.

The main point that I have observed is that the effective result is a clean continuous flash in FP mode. If it were in bursts of light, it would have really bad effects on the image of a fast-moving subject.

Hello Russ! Thank so much for your Tutorials.I have a question:You wrote "To make the flash primary, you have to make the flash overpower the ambient light. This must be done with the flash in iTTL mode by decreasing the exposure by three stops or more with shutter and ISO from the ambient setting you measured with the camera meter above."

why don't close the Aperture to make the flash primary too?

And for the secon scene: HOW TO BALANCE THE FLASH TO MEDIUM AMBIENT CONDITIONS

you write: "You might be tempted to use camera A mode, and it can be done, but you have to be very careful to prevent overexposure. The shutter is limited to 1/250th (or 1/200th) flash sync speed, and since it can't go any higher than that, if you choose an aperture that is too wide, the shutter will bang into the limit and your images will all be overexposed. P mode fixes this problem."

But why not using FP Short Shutter here? than in A Mode the tie would be shorter than 1/250. And the power must be enough too because I just will fill the darks or make an saccent. So what is my fault in thoughts here?Thanks

First, I guess you missed my comment at the beginning of this post "NOTE: For this post I am assuming regular flash sync - Not Auto FP High Speed Sync".

For a basic cookbook, I purposefully avoided the more advanced topic of FP Sync on purpose.

I always recommend using regular flash sync unless there is a compelling reason to use FP Sync, because FP sync reduces the maximum flash power to only about 1/3 of the power that is available when using regular flash sync. This greatly reduces flash range.

I actually wrote a separate blog about this. Did you read it?

Summarixing from that blog:

...as long as you only need a small amount of fill, then FP mode is wonderful. I use it all the time for outdoor portraits when close to my subject. Then, I can use camera A mode and TTL-BL with a wide aperture, let the shutter increase as much as necessary, and still blur the background for isolation.

Thanks for your cookbook tips - these are great. Just a couple of questions.

My first is, should you use matrix metering to measure the ambient light i.e. when flash turned off.

Secondly if you find you are in low ambient conditions, you recommend the following settings:

"Camera Manual, Flash iTTL, ISO 400, f/4.0, 1/80th shutter."

You then say that "the flash system will control the exposure of the subject no matter you do to the ISO, Aperture, or ISO (within the range limts of the flash)." and that "The shutter will primarily control the background exposure."

What if you want to increase the depth of field - if you increase the aperture would this not then increase the amount of ambient light and thus cause overexposure etc? Or am I correct in assuming that if you stop down the aperture to increase dof you must then adjust the shutter speed accordingly?

My third question is regarding how to remove the ambient light - could you set the aperture to what you wish i.e for dof and then turn off the flash and then take a series of shots adjusting the shutter speed until you have a completely dark image? Then turn on flash and fire away at these settings?

1) Yes, Matrix metering does the best job of measuring the ambient light.

2) The flash exposure system will maintain a constant brightness of the SUBJECT no matter what you do with the ISO, Aperture, or Shutter. For instance, if you close down the Aperture, the flash power will increase to keep the subject at the same brightness. However, closing down the Aperture will cause the background to darken, because even though the flash power has increased, the square law tells us that it has a much greater effect on the subject than the background, due to distance. And, yes, the aperture does change the ambient contribution. If you opened up the aperture to reduce the depth of field, you could produce overexposure if the ambient light began to contribute significantly on the subject.

Shutter, however, has no effect on the flash, so as you change shutter, the flash power stays constant and only the ambient light in the background is changing in the exposure.

3) I use only the shutter to control the ambient for two reasons. First, the aperture causes flash power to change, so its effect on the ambient portion of the exposure is not easy to determine. And, second, the aperture usually has to be nearly wide open just to give enough flash range for practical use. If you set the aperture on f/8, for instance, the effective range of the flash would usually be less than 6 feet, assuming you are bouncing.

When I shoot flash, I use f/2.8 to f/4.0 as the limits of the aperture range. Once in a while when shooting a small group I get really close and use f/5.6 to try to hold focus better across the group.

So, the answer to your question about adjusting the depth of field is that you usually have to live with what you get between f/2.8 and f/4.0. You simply cannot adjust the depth of field to what you want.

Put simply Russ your CLS Practical Guide is one of the best and most imformative on the web!

My query is regarding 3rd party flashes in particular the Nissin DI866 which is aimed at somewhere betweeen the SB-800 & the SB-800.

A nice review here.http://dpanswers.com/content/rev_nissin_di866.php

Unfortunately the SB-800 has been discontinued and the SB-900 whilst an excellent flash is about $800 here in NZ.

So i'm seriously looking at the DI-866 for my flash needs especially at half the cost of a SB-900.

Would like to get your opinion on this flash and whether you see any short comings. It seems that the auto fp sync mode is considrably less than what Nikon offer, but still the cost to feature ratio is very good.

I have looked at the Nissin Di866 in the past, but the one mode I think it is missing that is pretty important is iTTL-BL.

iTTL-BL is used all the time when outdoors in daylight for automatically adding the proper amount of fill when shooting quickly (like weddings, etc). You don't have time to set up the regular iTTL mode and get it balanced with the ambient correctly. I usually use P mode with iTTL-BL and let the camera handle the balance. That way I can concentrate on getting the framing right in the very limited time I have to take the shot.

Now, it may be that the DI866 Auto mode does the same thing as iTTL-BL. That's something you should investigate immediately if you decide to get this flash.

I am glad to hear that FP mode works correctly when the flash is on-camera. That's when it is most important. I never use FP mode when the flash is Remote, so that wouldn't be a limitation to me.

You use FP mode in conjunction with TTL-BL when taking portraits outdoors in daylight. That allows you to open up the aperture wide open to blur the backgtround and still add the correct amount of fill. However, the maximum available power in FP mode is only about half that of normal mode, so range is somewhat limited. It would be interesting to know whether FP mode will work with the 'Auto' mode on the DI866.

so further to my last point, if I say set the aperture to f4, would you recommend my technique for removing the ambient light i.e. turn off flash and then adjust shutter till have a black image and then turn flash back on?

So as I udnerstand when shooting with f2.8-4 the dof will be quite small especially with portrait work. At f2.8 a lot of the face will be oof with a bit less at f4. Not ideal for group shots or if you want to get more of the frame in focus.

Yes, except, when you set the shutter, don't make the exposure without flash completely black. Set it to allow the background to show just a bit. The subject will almost always be darker than the background, so the flash exposure will work just fine.

When shooting group shots with flash, you may want to use f/5.6 or even f/8 to get a little more depth of field, but remember that your flash range at f/8 is only 5 or 6 feet when bouncing.

However, the most important thing when shooting a group is to place each member of the group as close to the plane of focus as possible. If there are multiple rows, make them stand touching each other, so the difference in distance between the front and back row will be minimized. (I wrote another blog article on this).

For portraits, f/2.8 to f/4.0 is usually what you want, so the background is nicely blurred. However, you can use just about whatever aperture you want, because you are so close to the subject.

Please understand that this 'cookbook' article is just to give you a starting point when you don't know what to do. Once you understand how to control the flash exposure, there are an infinite number of settings you can choose that will all work well.

I took some shots at f4, iso 400 and a shutter speed of 80 and they look good, from about 2m. I also took some shots at F2.8 - these are overexposed. With the flash off the f2.8 shots are black, so as I understand no ambient light. Why would I get overexposed shots at f2.8 - I thought the flash would adjust so correct exposure?

Hi Russ, just thinking out loud now - when I took the shot at f2.8 and it was a little overexposed, you said I was a little too close potentially. Other than moving back a little distance, could I change the iso down to iso200 instead of iso400 - as I understand increasing the shutter won't effect the exposure here. For example if I was limited for space. Have I understood this correctly?

got a wedding tomorrow and getting a bit jittery now! I try and shoot mainly reportage style, however, the bride and groom will want a few group shots etc so I was thinking if can shoot outdoors of using Fill Flash / TTL-BL in P mode. However, what if it selects a shutter speed less than say 1/60th will this not mean there is a risk of motion blurring? What settings would you recommend for groups shots of say 4 or more people? Thanks

Don't worry about P mode outdoors in daytime. It will never select a slow shutter speed anywhere near 1/60th. In daylight, it will usually select something up in the 1/800th range or higher. In fact, 1/1500th or higher is common if it is bright.

Just be sure to use TTL-BL and try to put the group in the shade. If the group is in direct sunlight, turn the flash down at least a stop or so IF there is any direct sunlight on any of the subjects. Remember the flash will add to any direct sunlit places and blow those spots out.

I know everyone tends to use now d300 or d90, but you forget us, the simple people, still using D70/D70s with flash sync speed of 1/500... So, in some details, we are an exception and some corrections have to be made...Good post, anyway... 10x

Well Wedding went well I think, maybe due to the sheer quantity of images I took, I was bound to get a few good ones! However, I did have some issues with the High Ambient shots.

It was a very, very sunny day so nice and bright - I selected P mode, ISO200 and TTL-BL, however, a lot of my shots were blurred. Looking at the settings, the camera seemed to select ISO100 most of the time, so this could explain it. However, I thought it would select something much higher as it was so bright. Not sure what happened or how I could amend this to ensure I get great shots all the time in these conditions. Perhaps I am better shooting A-priority with no flash when it is so bright?

The low ambient shots worked well on the whole, though the very dark room I found when I did my reccy became not so dark as it was so bright outside - instead I had medium ambient conditions! This threw me I have to admit and I had to guess the settings.

I also discovered that when shooting in low ambient conditions, rear synch should be selected to avoid the forward blurring on fingertips etc - is that correct?

I still use my D70, too! I used it as a second camera when I shot a wedding just a couple of weeks ago. It is a great camera!!

My main camera is now a D3, however.

Anyway, I went back through this post and I didn't see anything in that wopuld be different considering the higher sync speed of the D70. Everything I said still applies, unless I midssed something.

As an aside. did you know that the D70 will actually sync up to its maximum 1/1600 shutter speed if you use an adapter in the hot shoe to generate a PC Sync signal to fire an external flash? I have been told that you can cover two of the contacts in the hot shoe that tell the camera that the flash is attached, and it will do the same thing (but I don't know which contacts).

If it is bright, and you are using ISO 100, and P mode, then the camera should have chosen a much higher shutter speed than 1/100th.

What was the aperture it chose?

Think about the Sunny 16 Rule. On a sunny day, at ISO 100, and an aperture of f/16, the correct shutter speed would be 1/100th. I have never seen the camera pick anywhere near f/16 in P mode. It normally selects something like f/5.6 and a shutter of 1/800th.

I think you had something set wrong on the camera. check your exif data and see if you really were in P mode. It sounds like you might have been in S mode and selected 1/100th shutter. Or possibly camera A mode with f/16 selected.

For the medium bright ambient conditions, you probably had lots of overexposures if you left it in regular TTL and didn't apply negative flash compensation. I often switch to TTL-BL and Camera P mode in medium bright ambient conditions and let the flash and camera figure it out.

I've just checked the exif data again and for the most part when in P mode it selected a shutter speed around 1/160 - occasionally it selected a much quicker shutter speed 1/800-1000 but this was rare.

However, there were some instances where it selected a much slower shutter speed which is where I saw most motion blurring. For example, one photo was F4.5, 1/80th. I had +0.3 EV and a focal length of 62mm, in matrix metering. This was at ISO 200. The shot was of a couple sitting in shade by a river, they hardly moved but I still got blurring.

No, I don't think it is a camera fault. I think it must have been darker than you thought. f/4.5, 1/80th, and ISO 200 indicates deep shade without a bright background. In this situation I would have bumped my ISO up to 400. That would have doubled the shutter speed.

However, 1/80th is still fast enough to stop casual motion. However, camera motion can easily cause blur at 1/80th if you are not careful. Are you sure it is not camera motion causing the blur?

If you will email me a couple of your images at russ@russmacdonaldphotos.com, I will take a look at them.

Thanks Russ, you may be right, maybe I was a little loose with my grip. I will practice tomorrow to see how I get on. Actually thinking about it, the shots that were 1/80th etc were in shade by a river.

I will try and email some pics across. Thanks.

To reiterate, for medium ambient conditions - I should shoot TTL-BL, Iso 200, P mode? As for high ambient?

When the ambient is at the dark end of medium, you have a choice: you can either shoot flash primary or fill flash.

If you shoot flash primary, then you increase the shutter speed to decrease the ambient contribution. You have to make sure you can make a dark image with flash OFF by increasing the shutter. Then, switch to regular TTL and let the flash light the subject.

If you decide to shoot fill flash, then you leave the camera in P mode and the flash in TTL-BL mode. At the very dark end of medium, you may also have to increase the ISO to 400.

Hi Russ, Thanks for a great blog on using the nikon cls. I have a question what settings do you use for candid shots at events or weddings where there are high ceilings. I was viewing one of your weddings "Amanda and Michael" and was wondering was that straight up bounce flash, or direct flash. For example do you use direct flash in program with TTL-BL. I am going to be shooting a 50th anniversary event and wanted some advice on setting up my camera and flash…

The reception for the Amanda and Michael Wedding was part indoor and part outdoor at night. I used used my camera in Manual mode and the SB-800 flash in regular TTL mode.

You should normally never use TTL-BL when the ambient light is low.

Outdoors it was pitch dark, with almost no lights even on the tables. People were eating their dinners without being able to really see their foor. Anyway, outdoors I used ISO 400, f/2.8, and 1/8th sec so I would bring some of the lights in the background into the exposure. You can use a very slow shutter like this when the ambient is nearly pitch dark, because there is no light to cause ghosting. Then the beckground registers a little and you get that golden glow back there.

Indoors, it was also quite dark, and I used my standard ISO-400, 1/80th shutter, and f/2.8. If I were shooting it today, I would close down a bit to f.4 or so to get a little more depth of field, but back then I used f/2.8 a lot.

I also used my Gary Fong Light Sphere on my flash both inside and out. I kept the flash pointed straight up. There was virtually no bounce inside because of a black ceiling and outside there is obviously never a bounce. The LS does a great job of diffusing the direct light even without a bounce, as long as you stay close to your subjects.

For your 50th anniversary shots, if you are indoors, I suggest you use Camera Manual mode, ISO-400, f/4 and 1/80th shutter. Put your flash on regular TTL and turn it down by -1/3 ev. That should get you very close to perfect exposures. Remember, it is better to underexpose than overexpose, because you fix underexposure, but you can't fix something that has been blown out. All my shots right out of the camera tend to be a little dark.

Yes, that does help, but I may have to set my aperture to 5.6 because I have the 18-200 VR zoom lense and to keep from dealing with the variable apreture, I use 5.6, I have a 50mm 1.4 lense but I may not have time to change it for a quick group shot. I was using 2.8 but a photographer told me that for people I should use F8 not to risk someone being out of focus because of the depth of field. Also, I have a Gary Fong LS, but I was trying to use Neil Niekirk techniques by turning my flash 60 degrees. This can be a challenge during an event.

Whoever told you to use f/8 must have been using a much more powerful flash, or maybe a bare flash. The reason he/she told you to use f/8 was to create even more depth of field in order to hold more people in focus, but the SB-800's that I use run out of power at about f/4.5 when using a diffuser. You might be able to use f/8 if you used a bare flash, but then the light would be harsh and unpleasant.

To use the 18-200mm as a party lens you will have to use a higher ISO. If you use ISO 800 with f/5.6 it will give you the same effective flash range as ISO 400 and f/4, which is the combination I normally use.

This should make your 18-200mm work pretty well as long as you stay within 15 feet of your subjects so you won't run out of flash power.

Don't get tempted to take long distance flash shots, because your flash will not have enough power.

Of course, the problem with using ISO 800 is that it can be noisy on some cameras. But it should be fine for reception type shots, because they are not normally enlarged bigger than 5x7.

If you will be shooting group photos, they may end up being enlarged to 8x10 or bigger, so try to use ISO 400 or lower for that. Sometimes it is better to use your bare flash and make sure you get a good exposure than it is to use a diffuser and underexpose badly, because that will just increase the noise in an enlargement.

For your 50th anniversary shots, if you are indoors, I suggest you use Camera Manual mode, ISO-400, f/4 and 1/80th shutter. Put your flash on regular TTL and turn it down by -1/3 ev. That should get you very close to perfect exposures. Remember, it is better to underexpose than overexpose, because you fix underexposure, but you can't fix something that has been blown out. All my shots right out of the camera tend to be a little dark.Russ, When I adjust for underexposure, am I changing aperture or shutter speed...if I start at 1/80th won't i end up with a shutter speed that is too slow to handhold?

You are adjusting for the ambient contribution. That can be done with either the shutter or the aperture.

The difference is that when you change the ambient with the aperture, the flash power changes automatically to keep the subject at the same brightness, and when you change the shutter, the flash power remains constant, because the flash occurs totally within the open period of the shutter regardless of the shutter speed.

I normally like to adjust the ambient with the shutter just because the flash power stays constant and that keeps the background brightness from being affected by the flash, and it eliminates the possibility that you will set an aperture that is too small for the available maximum flash power.

If you don't understand what I am writing, I recommend you go back and read my early blog articles, 1) through 5). You have to understand how the flash and camera work together.

Hi Russ,I have read your article #18 - Camera & Flash Cookbook for Any Lighting Situation. That's something I've been looking for in order to know what to do under all different situations. I assume you are referring to an external flash under any of the conditions. Will all the rules apply when using the built-in flash on a D300? Or are there any exceptions? TIA.

All of the things I wote apply to both the pop-up flash and an external flash.

The key thing to understand with the pop-up flash is that you can set it in TTL-BL mode by using Matrix or Center Weighted metering on the camera, and you can put it in regular TTL mode by using spot metering on the camera.

Then, all the concepts are the same as when using an external flash.

However, you have to remember that the pop-up flash is much less powerful than the external flashes, so it may not have enough power to 'overpower' the ambient in medium ambient situations.

Also, it is important to understand that the lighting conditions overlap, and there is often more than one 'right' way to set the flash.

For instance, you might decide that the lighting is at the very low end of medium brightness. You could try using the low ambient approach (overpowering the ambient)using regular TTL or the balancing (fill) approach using TTL-BL. Both could work just fine. The results will look different, but they could both be good exposures.

Thanks Russ for your quick and helpful response. I have yet to find someone who can be as helpful and knowledgeable as you on flash photography. There might be people who knows more than you, but nobody can explain things as good as you do. Thanks again.

I have been reading up on flash lighting for Nikon systems for quite a while now trying to find some consolidated information from someone who can explain this in - shall we say - normal-human-being-readable format and boy-oh-boy, you've made my week!

I would like to thank you for he time you have taken to provide all of this information to the general public - I will be referring back to your blog several time and will most definately recommend others to read your blog and tutorials!

I have been reading up on flash lighting for Nikon systems for quite a while now trying to find some consolidated information from anyone who can explain this in - shall we say - normal-human-being-readable format and boy-oh-boy, you've made my week!

I would like to thank you for the time you have taken to provide all of this information to the general public - I will be referring back to your blog several times and will most definately recommend others to read your blog and tutorials!

First I want to say thank you for answering my question about Neil's book.

I have another question but this one is about film. How these "recipes" applies to film photography? I just got an used F100 and I have the SB-800. I think with the F100 I won't have the TTL-BL but TTL will still work. Also I understand that I will have to work around the film I will use on any occasion. But just as a general idea do you think I can apply all the great info you have on your blog into film area?

Film TTL works extremely well, but totally differently than CLS. It relies on the reflected light from the film itself to turn off the flash. There are no 'preflashes'.

The SB-800 was designed at the time when film was still king and digital was just starting. As such it is fully compatible with film TTL, including TTL-BL. The thing it won't do on a film camera is the CLS wireless mode, but it does have the SU-4 mode, which is how we did it prior to CLS.

Almost all of the information in my blogs is directly applicable to film.

As I'm pretty new to photography, I am a Flash novice as well. I read most of your blogs and "think" I understand most of the things: wonderful explanations.

However I do not understand why "you normally like to adjust the ambient with the shutter just because the flash power stays constant and that keeps the background brightness from being affected by the flash". If the power of the Flash is adapted, the relative exposure of background and subject remain the same, right?. The backgroung gets more/less light, but that effect is compensated by the different aperture, so I don't see the problem (or does it have to do with mixing light colours?)

Also, the switch from TTL to TTL-BL has to be done by switching between matrix and spot metering in case of the pop-up Flash. I have an SB-700 and I have the impression that also here I can only switch by switching the metering. Does the SB-800 have a dedicated switch for that?

I'm not exactly sure I know what you are asking, so I will try to answer your question by explaining it again.

When you adjust the aperture in a flash shot, the whole image brightness changes. When you adjust the shutter, only the ambient changes.

The flash power remains the same as you change shutter, because the entire flash pulse occurs while the shutter is fully open, regardless of the shutter speed. This means the shutter will have no effect on the flash.

If you are close to your subject, and the background is far away, then the flash will be providing most of the illumination of the subject, but it will not be adding anything to the background. The background will be mostly illuminated by ambient.

So, in that case, if you adjust your shutter speed, the background will change brightness, but the subject will stay the same brightness (mostly). There will always be a slight change of brightness of the subject, because there is a small amount of ambient on the subject, but it is usually so small you can't see it.

When you adjust the aperture in a flash picture, both the ambient and the flash contribution change by the same amount. This is because both have to pass through the aperture and its size will affect how much passes.

TTL and TTL-BL on the SB-700: I don't own an SB-700, but according to the User's Manual, you are correct. It works just like the pop-up flash on other cameras. I need to mention this on my blog, since it is the only full-CLS flash that works this way.

Page C2 in the User's Manual explains it like this:

"• When the camera’s metering mode is changed to spot meteringwhile i-TTL balanced fill-flash is in use, the i-TTL mode automaticallychanges to the standard i-TTL mode.• The i-TTL mode automatically changes to i-TTL balanced fill-flash, after changing the camera’s metering mode to matrix or centerweighted."

Also, you will see 'TTL' or 'TTL BL' in the flash display on the flash depending on which metering mode you select.

Thanks for the quick reply. I guess I was (am) confused by the second part of your statement (the background brightness is not affected by the flash power because the power stays constant). I am aware that the ambient light is changed by the shutter (that's the very important message of your first blog about the 2 metering systems, right?). However, I am confused about your statement that suggests that you need to keep the flash power constant to prevent the background brightness from being affected by the flash. If you decrease the aperture the power of the flash is increased, the subject and background get more light, but finally the background and subject brightness in the final picture are the same as with a larger aperture, I would think. So, in that sense the background brightness (relative to the subject) remains the same when you change the aperture, so the background is not affected in the final picture. Does that make sense, or do I have to go back and read your blogs again?

About the SB-800 you are using: does that have a separate button/menu option to switch between TTL and TTL-BL irrespective of the metering system?

The exact text that I wrote was: "I normally like to adjust the ambient with the shutter just because the flash power stays constant and that keeps the background brightness from being affected by the flash..."

I tried to explain this in my previous answer to you.

Yes, it is true that when you change the shutter speed, the flash power stays constant.

This is because the entire flash pulse is so short that it starts and finishes within the time the shutter is open.

Maybe the real issue is that you don't understand how the flash changes power?

When we talk about changing the 'power' of the flash, we are not being totally accurate in our word choice. When we change the 'power' of a flash, what we are really doing is changing the length of time the flash pulse stays on. To be totally correct, we should say that we are changing the 'effective flash power', because the actual power of the flash pulse itself is always constant.

Changing the 'power' changes the effective power by changing the length of time the flash pulse stays on. If the flash fires for a longer time period, then the effect is as though it fired at a higher power.

Then, if the entire time the flash is on occurs while the shutter is open, it doesn't make any difference what shutter speed is selected. The effective power of the flash will stay constant. We simply shorten this to say that the flash power stays constant, while understanding how it works.

On the other hand, when you change the aperture, the flash power changes to keep the BRIGHTNESS of the subject constant.

In any case, the flash will not affect the background brightness significantly, as long as the background is more than twice as far from the camera as the subject is. The square law says that each time the distance is doubled from the flash, that the power will be reduced to 1/4th what it was.

For instance, with the subject at 5 feet from the camera and a background at 20 feet, the background will only receive 1/16th the amount of (effective) flash power as the subject. That means the flash will still have some effect on the background, but it's usually insignificant.

Sorry, but I don't think we will get this sorted out. Perhaps I am missing something.

But just to end: suppose subject at 5 feet, background at 7 feet.

Picture 1: aperture 1 / shutter speed 1

Picture 2: aperture 1 reduced by 2 stops or so / shutter speed 1.

I would think the flash power is higher in case 2, so both subject and background get more light (background brightness only 2 times lower than subject brightness, so still effected by the flash). Because of the lower aperture, the higher illumination by the flash nevertheless results in the same final picture brightness.Is this right, i.e. could you say if Picture 1 would look different than picture 2 w.r.t subject and background. If they are the same, than we are on the same track. If yes, than I am certainly missing something important and need to study again.

But the reason you are correct is that your situation has violated one of my basic constraints. You have placed the background too close behind the subject. When the background is this close, it will be greatly affected by the flash.

None of what I have been talking about, ie controlling the brightness of the background independently from the subject, will work unless the background is at least twice as far from the camera as the subject. Even then, the beckground will be affected at 1/4th power.

Also, if you are in a small room where you are getting a strong ceiling bounce, my comments don't apply, because the reflection 'channels' flash power to the background.

What I am talking about works in a large ballroom or church, where the subject is very close and the background is very far, and there is minimal ceiling bounce.

Yes, in TTL operation, when you close down the aperture, the power of the flash increases to keep THE SUBJECT at the same brightness.

However, if the background is close, like in your example, then the flash will also keep the brightness of the background the same.

Specifically: In case 2 the flash will be at higher power and both the subject and background will remain the same brightness as you change aperture.

I think the whole reason for your questions is because you were not thinking of the the background being far enough behind the subject. It has to be way behind the subject or the flash will affect it. However, the flash power falls off quickly (square law), so it doesn't have to be quite as far back as most people think.

Maybe that helps?

Also, please feel free to email me with additional questions on this at rkmacdonald@gmail.com.

You asked:"About the SB-800 you are using: does that have a separate button/menu option to switch between TTL and TTL-BL irrespective of the metering system?"

Yes, it has a menu option to select either TTL or TTL-BL regardless of the metering mode.

However, if you are in TTL-BL and you change the metering mode to Spot Metering, it forces the flash to switch to TTL. TTL-BL depends on receiving brightness information from across the whole frame, so it can balance the subject brightness to the background. Since Spot metering provides no brightness information from anywhere except the subject, TTL-BL can't work.

Thanks for the clarification. It is clear to me now. I was indeed thinking of the background being close to the subject. Keep up the good work. As I said, I am very new to DSLR photography and your explanations/blogs were extremely useful so far.

Now I am able to do really grat shots with the SB900. Of course there are some things I 'm not sure everytime but with training it will work. I'm shure.Did you ever think about writing a book with all the knowledge about this?Special the additional tips in the comments are a little bit hard to read. It would be great to make a new blog topic with the main questions you answered. Or writing the mentioned book.

No, I don't think I will ever make this info into a book. This is my hobby, and a book would be way too much like work!

However, I do plan to rewrite each blog to incorporate the most significant comments. The only problem is in finding the time to do that. My photography business is growing quickly right now, so my time is very limited.

Hi Russ!I think I understand what you mean.A book seems to be a further step.I would be very interested (And I'm sure I am not the only one) in new pictures from you.May you have time und make a new blog entry just with a few examples (in the best way certainly shot) and a short story how you did it.

And as I said before. Yes, a rewrite of some articles (including the great support from the comments) would be fantastic.Thanks again Greedings from Austria

Thank you, Russ, for explaining the CLS system and it usage in wonderfully simple and beautifully clear terms. For the first time since opening the box containing my SB-600 back in 2005, I have hopes of actually being able to use it effectively.

All your info has been so helpful. I bought the SB900 last May and have been confused on how to use it effectively...actually afraid to use it at all. I think I'm "getting it!" Thanks for all the blog posts...I will be back lots.

Hi Russ,i just found your blog today while searching for CLS answers.my question is the best way to use CLS with a non CLS flash?i am using a d300s (just bought it and still learning it all) with a sb800 and all is fine. but when i bring out the sb26 set up as a optical slave, the preflashes are screwing things up.i thought by setting the sb800 to manual would halt the preflashes? and i also thought using the FV lock would halt them after the first fire?i am now thinking i should use the pop up in manual set to -3 and trigger both strobes in remote?any suggestions? and if you have already covered this, please send me to it!

I have not directly covered your questions in my blog, but I have discussed one of the ways to eliminate the preflash; use Flash A mode.

It is very difficult and usually impractical to use CLS together with non-CLS flashes. The CLS system always fires a preflash prior to the shutter opening that will fire your optical slave. Since the slave fires before the shutter opens, it does not contribute to the exposure.

If you want to use the CLS flash in iTTL mode, there is only one way that I know of to fire a strobe at the proper time. You have to attach an external flash (or SU-800) into the hot shoe and a PC Sync cord from the camera body to the strobe. Then the strobe will fire after all the preflashes go out. I have used this technique to add a background light in my studio.

This will not work, however, when using the pop-up flash, because the pop-up flash disables the PC Sync output as soon as you pop it up.

Your question was not clear about Manual mode.

There are two different kinds of Flash Manual modes: 1) Full Manual, and 2) Commander Manual.

In Flash Full Manual mode your external flash must be in the hot shoe and set to Manual mode as displayed on the back of the flash. In this mode, there are no preflashes, so it can be used to fire optical strobes.

The pop-up flash can also be used in Full Manual mode as set in the camera menu, and it will not make any preflashes, so it can be used to fire strobes.

In Commander Manual mode, there must be a Commander on the camera and a flash in Remote mode. Then, you tell the flash to fire in 'Manual' mode via the Commander Menu. In this mode, there are still preflashes sent to tell the Remote flash to fire in Manual mode. These preflashes will fire any optical strobe early.

There are also two non-CLS modes on the SB-800 that do not fire preflashes: 1) SU-4 mode and 2) A mode. Both require the flash to be in the hot shoe.

Place the flash in the hot shoe and select SU-4 mode, and then set the power of the flash on the back of the flash. No preflashes will be fired.

To select 'A' mode have to go into the flash menu. Then, place the flash in the hot shoe and set the aperture you are using into the flash. Note: the SB-800 AA mode still fires a preflash. (See my blog #13 on this subject).

i just made the upgrade from a D100 where i would either fire the sb800 with a sync cord or optically, and fire the sb26 as a optical slave and i got used to doing it this way.i will enjoy CLS when using the sb800 by itself tho! i guess i can continue this way until i locate the moola for another sb800 or 900!

The way you stop action with a flash is to shoot in low ambient conditions and block the ambient with the shutter. For instance, the flash will stop action indoors in a basketball game if you increase the shutter speed to block the ambient and use the flash in regular sync mode.

Outdoors in bright daylight the flash will stop action, but on top of that will be a blurred image from the ambient, because the highest shutter speed you can select is flash sync speed (around 1/250th).

So, outdoors in bright light, you have to use a high shutter speed (1/2000 or higher) to stop the action. You can use the flash in FP mode with this high shutter speed to add a small amount of fill, but the flash will not be stopping the action.

Thanks Russ, I will try. One more question. Maybe I'm not familiar with my new SB-600, but I can see the TTL, TTL BL and FP signs on the back of the flushgun only when it is placed on the camera. When I use it wirelessly I can't see all these options, even though I set it on TTL in my camera menu. Could you please explain that?Thank you

Hi Russ,Thanks so much for this information. I had a very basic question and am not sure if you are still answering questions on this blog.

Regarding the basic settings that you mentioned for Low, medium and high ambient. Are these settings based on direct flash or diffused flash straight onto the subject? How would these settings vary if I bounce the flash all the time? typically in weddings, bouncing the flash is preferable and want to know what would be the setting.

Great article and you've done an amazing job at summarizing you previous ones in a cookbook style. Very useful indeed.

One think I still cannot wrap my head around is that why did you suggest to use Camera Manual mode initially to determine ambient light conditions. Isn't it easier to use Aperture mode, since we have fixed the ISO and Aperture and let camera meter the appropriate shutter speed. This way I can get the exposure numbers in one shot, rather than setting shutter manually in Manual mode.

Hi Russ,I have been practising your methods since the day I discovered your website with success and joy.Thx again for these great explanations about the flash photography and making such a complex topic easier and fun.I have learned a lot from your blogs and continue learning...

Some (not every) of my flash photos lack sharpness which I have just realized and I wanted to get your opinion about the possible reasons for that.

below is the exif data of a flash photo which I found it soft although it had to be very sharp with the settings below...

nikon d7000on a tripodvr off35mm nikkor lens

f91/250sprogrammed automatrix meteringiso 100af-swide area

sb600i-ttl-blfront curtain-0.3ev

april17:19 pmsunny and bright weathersun is behind the camera

the only possible reason that I can think of is:I set the camera to self timer mode and set it to 8 photos with a 2 second delay.(But I am pretty sure that the flash triggered on each 8 photos)and I can say 5 or 6 of the 8 are not sharp enough.

can this lack of sharpness be bec of this self timer settings or not?I really wonder what causes this?

Could you elaborate more on the flash range? For example, how do you know that at F8, the effective range of the flash will be within 6 feet? How did you come to this number? Is there a way to calculate this?

Great info! I've been working on improving my flash photography, even more so now that my sis got me an off-camera flash (I didn't even know there was a place to get a camera flash in Beaverton, OR). I'll have to keep these notes handy!

So much useful information. I read through and went ahah! in nearly every post. Thunder bolts of understanding and general relief, I had finally found some clear information I could follow. Thank you so much for putting this all out there.

About Me

I'm a retired Electrcal Engineer (MSEE USF 1975) now 11 years into my second career as a Photographer. I shoot mainly weddings, events, and portraits, but have also been doing some landscapes for fun.
I decided to start this blog to capture some of the many Nikon Speedlight posts I've made on http://Nikonians.org/forums . Of course, the main reason this is needed by the photography world is that Nikon, who makes the world's best Flashes, doesn't do a very good job of documenting them.
I am also a Commercial Pilot and an FAA Certificated Flight Instructor (CFII).